In recent year, with progress of technology and improvement in life quality, apart from price and endurability, people start to consider convenience, accessibility and safety of product for purchasing a novel product. Subject to the change of such market trend, various manufacturers must continuously make in an effort to develop novel and more progressive products to meet most customers' demands. A knife usually carried during an outdoor leisure activity is taken as an example below. A folding knife becomes a popular type of knife because of meeting both portability and safety, and every manufacturer pays attention in improving detail structure of the folding knife for better endurability and more smoothness in use.
Please refer to FIG. 1 which shows a schematic structural view of an inner structure of a conventional folding knife 1. The folding knife 1 includes a blade body 11 and a handle 12. The blade body 11 is pivotally connected to a position on the handle 12 and adjacent to an end of the handle 12. The handle 12 has a resilient plate 121 and a lockback element 122 inside. The resilient plate 121 has an end fixed on the handle 12 and adjacent to other end of the handle 12, and other end movably located inside the handle 12. The lockback element 122 has a middle section pivotally connected with the handle 12, an end extended to a position adjacent to an end of the blade body 11, and other end abutted against the other end of the resilient plate 121, so that the lockback element 122 can be pushed by the resilient plate 121 to enable the end of the lockback element 122 to push the end of the blade body 11 for firmly locating the blade body 11 out of the handle 12. The lockback element 122 has a press portion 123 corresponding in position to the resilient plate 121. When wanting to receive the blade body 11 into the handle 12, the user can press the press portion 123 to release the end of the lockback element 122 from the end of the blade body 11, to enable the blade body 11 to rotate towards the handle 12 for being received into the handle 12.
The conventional folding knife 1 having aforesaid structure enables the user to control the receiving of the blade body 11 conveniently by hand in a press manner. However, the inventor observes recent market trend and finds that the consumer considers not only basic factors of convenience, portability and endurability of a knife product but also the applicability of the knife product for meeting the consumer's demand, while purchasing the knife product. The reason is that the knife products are divided into more and more types, for example, types of the blades include plain edge and serrated edge. The blade with the plain edge has a smooth cutting edge for precisely cutting. The blade with the serrated edge has a larger contact area during cutting, so that the user can save force. Each of the plain edge and serrated edge has its advantage and drawback, so a knife product having part serrated edge is provided in market correspondingly.
The knife products have more sophisticated classification, so the consumer must consider purchase cost, usage and application level while purchasing the knife product. Therefore, the inventor improves the existing knife structure to design a lockback tool with replaceable workpiece, thereby reducing production cost and solving a problem that the consumer is not easy to adapt a new tool structure. In addition, the inventor further finds that other tool products (such as chisel, axe, screwdriver and so on) also have the same problem. Therefore, what is need is to improve the existing knife structure based on the concept of replaceable workpiece, so as to design a tool with easy-replaceable workpiece.